Navigational and drafting instrument



- May 23, 19H39-v LfM. MccLusKr-:Y

` NAVIGATIONAL ANDYDRFTING INSTRUMENT y Original Fi1e`d July 28. 1937 3 Sheets-Sheet l May 23, 1939. L.. M. MccLusKEY 2,159,562 y ruwmA'roMIJ A ND DRAFTING INSTRUMENT."

Original Filed July 28,1937

'3 Sheets-Sheet May 23, 1939, L. M. MccLusKEY I NAVGA'IIVONAL AND DRAFTING INSTRUMENT O riginal Filed'July 28, 1937 3 Sheets-Sheet 3 Patented May 23,v 1939 PATENT oFFlcE NAVIGATIONAL ANDl DBAFTING INSTRU- MENT l l um, M. Mccimkey, Portland, Maine Application 6 Claims.

H This invention is a novel drafting instrument, "particularlyj adapted for use in determining courses 'upon charts or maps between known posivtion line to or fromfthe compass'roseof the f Vychart or map which shifting operation, aside `from its inherent inconvenience, usually results in unwarranted inaccuracies in the bearing calculations. f

The'principal object of my invention is to provide an instrument which obviates the necessityof moving or shifting same when once set upon the desired course, 'the instrument comprising briey a rectangular transparent base sheet, any long l edge of which can be placed on a chart along the course, said sheet having aicompass rose or circle; also a substantially square transparent indicator sheet rotatably mounted on the base at ycorners overlying and cooperating therewith, said indicator sheet carrying a T-square slidably mounted in guides,the head of which T-square 1 being adapted, through rotation of Ilthe indicator 'sheet and axial movement of the T`square in its guides, to be brought into coincidence with any meridian of longitude either to the right or left ,of the base, with any parallel of latitude either kabove orv below the base,` or in fact with any lines parallel therewithsuch as the borderlines of the chart, while regardlessof the particular setting of the T-square the ysame reading of thebearing will always be obtained using as an indicator` the particular corner of the indicator sheet which in anyfposition of the T-square is pointingy directly towardsr the user, i. e., to the bottom o! the chart, the reading indicating directly the s particular degree or point of the bearing without reference to any lcompass rose which may be 45 displayed onr the chart itself, thereby rendering theinstrument particularly' adapted forf-use by" aviators and small boat navigators where facilities for spreading outy large portions of a chart on a table are lacking. n y

Another object of the invention is to provide an instrumentY of the above character with a second square indicator sheet carried by the first indicator sheet, same being similar in size and yshape thereto and being adjustable thereon to 55 indicatethe magneticcoursaas distinguished thechart or map to transfer the desired directhe axis of the compass rose and having its four July 28, 1937, Serial N0. 156,221 Renewed April 11, 1989 from the true course, for the particular location covered by the chart.' the proper one of the four corners of 'the second sheet according to the setting of the T-square in the manner previously described with'reference to the first sheet, in'- dicating directly on the compass rose of the base the magnetic course, without reference to any compass rose carried by` the chart..

A further object of the invention is to provide an instrument of the above type which will be 10 useful in oillce, factory, school, or drafting room as a generaldrawing tool.. same taking the place 4of ordinary tools such as protractors, T-squares, triangles, ruler dividers, parallel rulers, and the l like.-

Other minor objects of the invention will be hereinafter set forth.

I will explain the'invention with reference to the accompanying drawings which illustrate one practical embodiment thereof to enable others familiar with the art to adopt and use the same; and will summarize in the claims the novel features'of construction, and novel combinations of parts, for which protection is desired.

In said drawingszf- Fig. l is a plan view of the complete instrument.

Fig. 2 is a longitudinal section on the line 2 2, Fig. 1.

Fig. 3Iis a transverse section on the line 3 3, Fig. 1.

Fig. 41s a plan view of the "true" course indicator sheet, detached.

Fig. 5 is a plan view of the guide forming members.

Figure 6 is a plan view of the "magnetic course indicator sheet, detached.

Fig. 7 is a plan `view showing various applications of the instrument to a conventional chart to determine the course between two known positions.

Figs. 8 and 9 diagrammatlcally illustrate uses of the instrument in plotting degrees relative to the axis of the base sheet.

Fig. 10 diagrammatically illustrates another useof the instrument as a bearing taker for ships or the like.

` Figs. 11, 12, 13, 14 diagrammatically illustrate various uses of the instrument for general drawing purposes.

The instrument The instrument comprises a rectangular elongated base sheet A of transparent material, such as Celluloid, although preferably of Lumarith" which is stiffer, non-curling, non-inflammable, and will permit direct printing of the compass rose thereon. On the longitudinal axis of the base sheet is marked or grooved an axial line A', and at one end (left, Fig. 1) of the base, coaxial with line A', is a compass circle A2 of diameter substantially equal to the width of the base. Circle 'A2 contains three-hundred and sixty divisionsvreading from the mark, at the adjacent end of the base, around the circle in an anti-clockwise direction, to conform with the present practice of marking Compasses in degrees only. However, to facilitate use of the .instrument by navigators, fishermen and pilots who still employ the former style Compasses which are marked only in points, I provide within circle A2 a compass rosevA:i divided into 128 divisions, the north point N coinciding with the 0 mark of circle A2, While the east point E, south point S, and west point W coincide respectively `withr the 90, 1804 and 270 marks of circle A2. Preferably the customary intermediate point notations, such'as NNE, NE, ENE, etc., are also displayed in roseAB. 'I'hus the provision of circle A2 and rose A2 will permit the navigator to work with either degrees or points'directly according to whether'his compass is marked in degrees or points, thereby obviating the necessity of translating degrees into points or vice versa.

Preferably a vmarked or grooved line A4 is provided in base A normal to the line Afat the axis 'of circles A2, A3 and passing through the 90 and 270 marks of circle A2. Adjacent the other end (right, Fig. 1) of base A is a somewhat' smaller circle A divided into four quadrants, the 90 marks of each quadrant coinciding with a line A6 normal to the line A' passing through the axis of circle' A5. At the axis of circle A5 is a circular hole A8 for the purpose hereinafter described. On base A parallel with the long edges are arrows A" pointing towards the'end (right, Fig. 1) adjacent circle A5, and associated with each arrow is the notation ,Direction of course. v

In base A at the axis of compass circle A2 (and rose A3) is an upstanding stud l (Figs. 2 and 3) carrying on its upper end a thumb nut 2 or the like, on which stud is rotatably mounted asubf stantially square indicator sheet B (Figs. 1 and 4) of transparent material similar to base A, said sheet B having a centrally disposed hole Bu for stud I, and having marked lor grooved lines IB',

` B2, B2, B4, respectively bisecting the angles at the f four equally spaced corners, said lines when indicator sheet B is in normal position shown in Fig.

1, being adapted to overlie the 0, 90, 1802 and' 270 marks respectively of compass circle A2, and

consequently to also overlie the point divisionsvr marked N,'E, S, and W, respectively of compass rose A2. Indicator sheet B' cooperatesl with the compass circle A2 and rose A3 as hereinafter explained to indicate the true course, as distinguished from 'the "magnetic. The notation True is preferably ydisplayed adjacent one of the corners of sheet B, as shown.

Indicator sheet B carries a xed guide for the shank of an axially slidable T-square C of transparent material, said guide being preferably composed of spaced parallel transparent members 3,

3 (Fig. 5) mounted on'the upperi face of sheet B adapted to engage the side edges of the shank of T-square C, said members 3, 3 being bridged by a transparent cover member I, (Fig. 5), the members'3 and 4 being connected together and to the sheet B by bolts for rivets 5, the shank of T-square C sliding between sheet B and topmember 4. Guide 3-'4 is so disposed on sheet B that the shank of T-square C will lie parallel With axial line A' when sheet B is in normal position on the base shown in Fig. 1.

The shank of T-square C has on its upper edge a marked or grooved scale C' indicating inches extending from the adjacent edge oi the head C4; and on its lower edge a marked or grooved scale C2 'indicating nautical miles, said scale C2 being preferably 1/80,000 to conform with that usually shown on coast and harbor charts. Scale C2 extends from a line C5 extending longitudinally of stud 6 opposite thel shank whereby the T-square C may be conveniently shifted axially of its guides 3 4. l

Between base A and indicator sheet B is a second substantially square indicator sheet Dv (Figs. 1 and 6) also of transparent material, and having a centrally disposed hole Do receiving said stud l uponY which said sheet is rotatably mounted. Sheet D is similar in size and shape to sheet B, same having marked or grooved lines D', D2, D3 and D4 bisecting its four equally spaced corners. spect to sheet B to indicate the magnetic deviation from the "true course for the particular location covered by the chart, the sheet B beingv provided with a hole B7 forI a stud l having its head slidable in an arcuate slot 8 of substantially 180 arcuate length in sheet D, the stud 1 carrying a thumb nut 9 or the like on its upper end. Indicator sheet D can thus be offset any number of degrees from the axis of "true indicator sheet B. Thus, if the magnetic variation for any location is 20A westerly, the axis of sheet D is oset 20 in a clockwise direction from the axis of sheet B, while for an easterly variation the sheet D is koffset in the opposite direction. Then when reading a course, sheet D will indicate directly the magnetic course without further calculation.

I n operation kor with any parallel of latitude on the chart, or

with any borderline of the chart, or any lines parallel therewith, and the course, either true or magnetic, readk directly` from the compass circle A2 or rose A2 of the base using the particular corners of the indicator sheets B or D which in the particular setting of the T-square C is pointingdirectly towards ,the user, i. e., towards the bottom of the chart, the reading being directly obtained without further computations or calculations and without reference to the chart'scompass rose. ,y

Fig. 7diagrammatically illustrates various ap- Sheet D is adapted to be set with relas list

plications ofthe instrument to a conventional chart 4to determine a course, chart F being shown as carrying a compass circle F of common form. In Fig. .7 theinstrument issfused'to determine,

the course, -in degrees,l between known points:

'and y. vBase A is placed on the chart with its upperedge on points x, u, and the head C* of the edge of head C* coincidesL with ameridian of longitude ,to the left of thejbase, marked P. TheA corner B2 yof sheet B which'is vpointing directly 1 tothe user, i. e., towards the bottom oi'A the chart, overlies the 63 vdivision mark .on compassl circle A2, directly indicatingithat .637k is the true course in degrees.

mark of compass circle A2, giving same course reading. If head C* of the T-Square is brought kinto position c (Figrll) coinciding; witha, me-l n v tighten nut 2.

ridian of longitude to the` right `ofvbase A, marked R, thecorner B4 4of sheet B whichisrthen point- .ingto` the usen/i. e., towards therbotto'm oi the chart, will also overlie the 63 mark encompass 1 circle A2giving the same course reading. Simipositions, dueto theutilization of the four corners thereof, will always give corresponding read- To plot piloting bearings such l and cross bearings, one can 'either use the instrularly, if the headC* is brought into positionA ,d

soy as to coincide with vthe parallel of latitude.,4 marked T, disposed below base A, the corner B'1 fy sheet B which isy thenpointingto the usery l fin that position of the VT-square, will also over lie the 63" mark on compass circle A2.- l Thus the settings of thev indicator sheet B in the various ingson the compass circle A2 of the base.

Obviously,instead of using the meridia-ns of A,latitude and parallels otlongitudethe .borderl linesof the chart may beutilized,v affording additional lines for determination of the coursewhere the instrument is used 'adjacent the corners or the borders of the chart.A If thevcours'e 1.11 is transferred to the compass 'rose F of the chart,"

usingparallel rulers or other means, the course would coincide with the 63 division of, the chartsy compass circle F, as indicated bythe dottedl line jx', 1J inFig. '7. 4Thus inFig; '7 the true course .is read oi the compass circleV A2 or rcompassrose` A? of the base directly without reference -toythe chart's compass rose F", and it'fis only `necessary f Vto navigate accordingltc 4the point orfdegree ,l :directly on the compass circle A2 encompass rose A3. f

Ori the compass r `magnetic variation for the` particular locality Vis A with respect to sheet B so `that in reading the instrument in any ofthe four positions a, b,

c,, and "d ofthe T-square shown, the magnetic fcourse will be indicated as 83.when thetrue 'ior - and use of ordinary course protractors.

course is 63. Y f

" Thus, in usin'gmy 'instrumentjonce thebase is set on the course desired, sameis never moved, eliminating inaccuracies occasioned by other methods necessitatingshifting of parallel yrulers .erato'r, while holding` the basey on the course on any part of a chart may bring the head C* ofthe i If `head C* ci the T-squari` isv y changed into position 1;,shownl inlFlg..7 with?, its outer edge coinciding-.with a'parallel o! latitude n disposedl above base A, marked Q, the corner'Ba f of indicator sheet B which in such position of the T-,square is pointing to the user; 1i. e'., 'towards the bottom of the chart, will also overlie the 611)',I l

rose F',ofchart F (iugm the `1 is about 45off port, whereas in Fig. 9 the object 3 `T-"siiuare to coincide with any line of latitude or longitude-near the course, or if desired even to vthe borders of chart, and may read directly in front of khim the true or "magnetic course to the exact degree without reference to the l c'art's compassrose, this feature enabling the operator to work on any portion of the chart even in anygivenlocality, and a navigator using his boat f vinthat general locality need never change its position oyer a period of years; also the operator can check-thel course irrespective ci its direction four or more different ways, eliminating former .ftrial,vmethods.

The instrument is so constructed that it can. be J used accurately. on uneven surfaces such as are to be found on boats and airplanes; in fact it can be used on a folded chart held in ones lap, and 7will still give any desired course accurately, quickvly, and with ease of operation.

To` draw a course in any direction to or from la given point, it is only necessary to set the corner of sheets B (or D) .pointing toward the user on the'degree, either true or magnetic, desired, then until vther head C* coincides with any line of longitude or latitude, and base A adjusted until any long edge thereof passes through the given point, t and then draw alinefalongsaid edge.

To plot a bearing from a given point, such as rsent out by'r'adio compass stations, or bearings from ships yto known objects, simply set the corner of sheet B (or D) towards the user on the desired bearing mark of circle A2 (or A3) and pull out T-square'C until the head coincides with any line of longitude or latitude, then vmanipulate base A until a long edge passes through the point, n andthe edgedenotes the bearing. i

` as bow, beam ment in the manner previously described, or, by removing T-square C from sheet B and by placing thehead of stud 8 of head C4 in the hole Al at the axis of circle A?. With base A aligned with the course, any desired bearing may be obtained by sighting along the shank of the T-square. rIiigss and 9 illustrate use of the instrument in plotting degrees of objects such as lighthouses,

buoys, etc., relative to the ships bow or beam, using the compass vcircle As and the T-square C. The head` C* o! T-square C is placed upon the small compass circle A` `on base A with the shank vsighted upon the object which may .be a buoy L, the axis of base A beingdisposed on or parallel with the course. The rear edge of head C* of the T-square will indicate on circle A5 how many degrees oi bow or beam object Lis, which in Fig. B

Lis about 45 abai't the port beam. v

To use the instrument as a bearing taker for ships, base A (Fig. l0) is disposed axially of the center line M of the ship M or axially of the ships compass. By sighting the shank of T- square C on any desired object, such as N, the angle from the bow or beam may be read directly upon the compass circle A2 of base A, irrespective of the distance of the object from the ship. I'his use of the instrument is valuable in piloting a ship when a continual check is required on lights, buoys, or other objects.

To measure nautical miles between two points, place comer B2 of sheet B on the 90 mark of circle A2, then tighten nut 2 and pull T-square Then the T-square'is pulled out C out so that the linev C5 of head C4 coincides with one point, and the line 'A4 on base A coincides with the other point, lthen read scale C2 (1/80,000) directly lbelow `line A4.

To layl offy long courses, y'place corner B2 of Sheet B on 90 mark of circleA2 and tighten nut y 2, then pull out T-square C to its'end. The upper edge of head C4 will then be in line with 'a long edge of base A, and a long course may be drawn by placing marks at upper edge of head C4 and at the aligned edge of base A.

My instrument will be found'useful in oii'ice, factory, drafting room, and school work, as 'a handy drawing instrument, same taking the place in many instances of T-squares, triangles, ruler dividers, parallel rulers, and protractors; also will be found useful to military olces in plotting gunning andk general tactical work; also useful in working out problems in celestial navigation for mark St. Hilaire, and time sights. f Figs. l1 and 12 illustrate various uses of the instrument in connection with van ordinary draftsmans board, and serving as a general drawingV tool.

Fig.' 1'1 shows a drawing'board G and an ordinary T-square H. LThe headC4 of lT-square C can be'adjusted along l-square' H, and base A adjusted upr 'and down upon the shank of T- square C, also adjusted to any desired angle. In Fig. l2 the base A is shown as engaging the shank of T-squareH, and the T-square C of the instrument adjusted to any desired angle on the base. y

Fig. 13 illustrates the use of the instrument as a combination T-square and triangle. The head C4 of the T-square C is placed along'the edge f J of the paper J, and the instrument is manipulated independently of any lother drawing tools,

the base A being'adjustable at any angle on the shank of the T-square, and may be moved to any position thereon.

In Fig. 14 the edge of the base A is adjusted along theedge J' of the paper J, and may be moved up and down. The T-square C may be adjustedy tov any desired angle, with respect to the base', and may be pulled into and out of th guide on the sheet B.

The instrument can also be used as a'gauge,

by placing corner Bzvon the 90 mark of circle A2, and manipulating the T-square in and out oi its guide, reading the measurements in inches (or other scale) on the shank of the T-square. The instrument can be used as a unit; or by pulling out the T-square, used as a general drawing tool, holding either the rectangular base or the head of the T-square on a base line, permitting one to draw a series of parallel lines at any angle.

I claim:

1. In an instrument of the character described, a base having a straight edge portion and bearing /a compass rose; ,a member having a straight edge portion and having Aa hub rotatably mounted on the4 base coaxially of said rose, said hub portion having radialy markings cooperating with the rose and disposed ,90 apart; Va second member mounted on the hub and having radial markings cooperating with the rose and disposed 90 apart, and means for adjusting the second member on the hub.

2. In an instrument of the character described,

a base having a straight edge portion and bearing a compass rose; an indicator rotatably mounted on the base coaxiallyof said rose and having radial markings' cooperating with the compass rose and disposed 90 apart; a T-square having a shank axially slidably mounted on the indicator; 'a Second indicator member mounted on the'rst indicator and lhaving radial markings cooperating with the rose and disposed 90 apart; and means for adjusting the second indicator on the iirst indicator.

3. In an instrument of the character described, a base having a straight edge portion and' bearing a.- compass rose; an indicator rotatably mounted on; the base coaxially of said rose and having radial markings cooperating with the compass rose and disposed 90 apart; a T-square having a shank axially slidably mounted on the indicator; one end of the head of the T-square terminating in the line of the straight edge of the base when the shank is parallel with the said straight edge.

4. In an instrument of the character described, a rectangularbase having a compass rose marked with 360 divisions reading in an anti-clockwise f direction around the rose, the and 180 divisions being disposed on a line parallel with the long edges of the base; an indicator member vrotatably mounted on the base coaxially of said rose and having radial markings cooperating with the rose and disposed 90 apart; a T-square having a shank axially slidably mounted on the indi- Icator member; the` head of theq T=square being normal to the long edges of the base and the markings' of the indicator member coinciding with the 0,-90, 180 and 270 divisions vwhen the shank is parallel with the long edges; and means for locking the indicator member against rotation.

5. In an instrument as set forth in claim 4; a second indicator member' mounted o n the rst indicator member and having radial markings cooperating with the rose and disposed 90 apart;

and means for adjusting the second indicator `member on the rst indicator member.

6. In an instrument as set forth in claim 4, the outer ends of the head of the T-square terminating in the lines of the long edges of the base when the shank is parallel with said long edges.

, LEROY M. MCCLUSKEY. 

